In hospitals and like health care facilities, it is routinely necessary to sterilize and maintain in a sterile condition a very large number of medical articles, such as surgical instruments and the like. In view of this, the use of disposable, self-sealing pouches has become increasingly widespread for convenient and efficient sterilization and sterility maintenance. The materials from which such pouches are fabricated can be readily selected to permit the pouches and their contents to be subjected to various types of sterilization processes, including steam, ethylene oxide gas, and radiation. Such self-sealing pouches can also be fabricated for non-sterilization uses. Commonly-assigned U.S. Pat. No. No. 4,276,982, to Sibrava et al., discloses one self-sealing sterilization pouch which has proven to be quite commercially successful.
Because it is vitally important that the sterility of medical articles in such pouches can be relied upon, it is extremely desirable for such pouches to be configured so as to provide a clear indication that they have been opened. Since such pouches are usually intended to be opened by pulling apart the pouch webs or by some other clearly visible permanent deformation of the pouch, it is desirable to provide some mechanism by which a visual indication is provided of any reopening of the pouch's access opening. Such tamper-indication assures that the access opening of the pouch has not been opened and then resealed, which of course could allow undesired contamination of the contents of the pouch.
The above Sibrava et al. patent teaches a self-seal pouch construction adapted to provide such tamper-indication. The pouch of this patent includes one pouch web of thermally stable plastic film, and a second pouch web of steam permeable paper, which may comprise paper or paper-like materials. To effect tamper-indication, the pressure-sensitive adhesive provided on the pouch for sealing its open end is selected so that reopening of the pouch's access opening after sterilization results in tearing or other visible deformation of the pouch's paper web.
While the above arrangement is quite effective, it does present some limitations in the materials from which the pouch can be fabricated since at least one of the pouch webs must be paper to provide the intended tamper-indication. Depending upon the intended use, it is sometimes desirable to provide a self-sealing pouch having webs both comprising plastic film. In some instances, the adhesive for sealing a self-sealing pouch can be selected to result in visible deformation of a plastic film web of the pouch, but this again presents limitations in the selection of materials since it can be desirable to fabricate a self-seal pouch from plastic film material having characteristics such that the film does not readily visually deform attendant to reopening of the pouch's access opening.
Accordingly, it is very desirable to provide a self-sealing pouch having a sealing arrangement which is adapted to provide tamper-indication without permanent deformation of one of the pouch's webs. By such an arrangement, greater flexibility is provided in the selection of materials from which the pouch webs can be formed, while visual tamper-indication is assured.